by Rick Jervis, USA TODAY

by Rick Jervis, USA TODAY

FORT HOOD, Texas â?? Jurors in the court-martial of Maj. Nidal Hasan will return to court Friday to resume deliberating murder charges against the Army psychiatrist.

The case went to the jury Thursday after Hasan declined to give a closing argument at his trial on charges of killing 13 people and injuring 31 others in a shooting spree here four years ago.

A military prosecutor, in his closing, pressed the jury of 13 Army officers for a unanimous murder conviction that could lead to the death penalty.

Col. Steve Henricks repeatedly emphasized the word "premeditation," and claimed that Hasan's use of laser sights "established intent to kill."

A day earlier, Hasan told the judge, Col. Tara Osborn -- with no jury present -- that he agreed that his crime was not "done under heat of passion." He added that "there was adequate provocation - that these were deploying soldiers that were going to engage in an illegal war."

Military prosecutors called 89 witnesses and entered hundreds of pieces of evidence detailing the gory scene at Fort Hood on Nov. 5, 2009, when prosecutors say Hasan opened fire on soldiers â?? killing 12 and one civilian â?? in a busy medical processing center.

Hasan, representing himself, called no witnesses on his behalf.

Hasan, 42, has admitted to being the gunman in the shooting. More so than guilt, a central question in the four-year-old case has been whether Hasan gets the death penalty or life in prison, said Geoffrey Corn, a former Army judge advocate who teaches military and national security law at South Texas College of Law in Houston. Hasan has been passive through the guilt phase of the trial in order to reach the sentencing phase, where he would have more leeway in voicing his opinions and could talk about what motivated him to turn his gun on fellow soldiers, he said.

"He really believes what he did was right," Corn said. "But he's not allowed to talk about that in the guilt phase. He only gets to talk about that in the sentencing phase."